*{
    /*初始化*/
    margin: 0;
    padding: 0;
}
body{
    height: 100vh;
    /*弹性布局*/
    display: flex;
    justify-content: center;
    align-items: center;
    background-color: #ffffff;
}
ul{
    list-style: none;
}
nav{
    /*固定定位*/
    position: fixed;
    width: 180px;
    height: 400px;
    background-color: rgba(63, 164, 208, 0.8);
}
.menus{
    margin: 50px 0;
    color: #fff;
}
.li{
    letter-spacing: 2px;
    font-size: 17px;
    font-weight: 600;
    padding: 16px 0;
    /*动画过渡*/
    transition: 0.3s;
}
.menus li:hover{
    background-color: rgb(82, 199, 204);
}
.li .fa{
    font-size: 20px;
    width: 50px;
    height: 20px;
    text-align: center;
    margin-left: 5px;
}
.li ul{
    width: 0;
    height: 300px;
    padding: 50px 0;
    background-color: rgb(94, 204, 188);
    position: absolute;
    top: 0;
    right: 0;
    overflow: hidden;
    transition: 0.3s;
}
.li ul li{
    padding: 16px 24px;
    /*文字禁止换行*/
    white-space: nowrap;
    transition: 0.3s;
}
.li:hover ul{
    width: 125px;
}
.li ul li:hover{
    background-color: rgb(94, 204, 188);
}